JPH07246459A - Filtering method in vapor phase soldering device - Google Patents

Abstract

PURPOSE:To prevent the contamination of the filtered liquid, and to improve the precipitation efficiency of impurities by a filter. CONSTITUTION:The inert liquid 3 is stored in a liquid storage part 2 of a vapor tank 1, and the liquid storage part 2 is connected to a sealed filtering tank 5 through a pipe passage 21 including a liquid discharging valve 4. The filtering tank 5 incorporates a cooling coil 6, a stirrer 7, and a temperature setting device 8, and is provided with a filtering pipe passage 22 to circulate the liquid by a filtering pump 9 through a filter 10 and a filtering valve 11. A pipe passage 23 including a liquid feeding valve 12 is branched from this filtering pipe passage 22 and connected to a liquid storage tank 13. This liquid storage tank 13 is connected to the liquid storage part 2 through the pipe passage 24 including the liquid feeding pump 14. The start and completion of the filtering is controlled by the temperature setting device 8, and the filtering is started when the liquid 3 is in the high temperature range, and the filtering is stopped when the liquid is cooled down to the normal temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtering method in a vapor phase soldering device.

[0002]

2. Description of the Related Art As shown in FIG. 2, conventionally, an inert saturated vapor phase VP formed in a vapor tank by evaporating from an inert liquid 3 stored in a liquid reservoir 2 of the vapor tank 1 After the reflow soldering is performed, the whole liquid 3 is discharged from the liquid reservoir 2 through the liquid discharge valve 4 to the sealed filtering tank 5 after the work in the steam tank 1 is completed.

The filtering tank 5 first operates the cooling coil 6 and the agitator 7 to cool the liquid to a low temperature range. When the liquid is cooled to the temperature set by the temperature setting device 8 (for example, normal temperature), the liquid is circulated for a certain period of time through the filtering valve 11 and the filter 10 by the pump 9 centering on the filtering tank 5 to perform the filtering process. The impurities (flux components such as rosin) are removed.

After the filtering is completed, the liquid is stored in the filtering tank 5 as it is. And steam tank 1
Filtering valve 11 to start working with
Is closed and the liquid feed valve 12 is opened, and the liquid in the filtering tank 5 is returned to the liquid reservoir 2 of the steam tank 1 by the pump 9.

[0005]

The filtering tank 5 is a tank to which the dirty liquid 3 is supplied from the liquid reservoir 2 of the steam tank 1, and the tank 5 itself is also dirty. Therefore, when the liquid filtered by the filter 10 is circulated in the filtering tank 5,
There is a problem that the tank 5 is contaminated by dirt.

Further, the filtering is started after the liquid is cooled to a low temperature region in the filtering tank 5, but impurities (flux components such as rosin) dissolved in the liquid at a high temperature region are filtered as the temperature decreases. Separated and deposited in the tank 5. The impurities deposited in the tank 5 remain in the tank 5 to contaminate the tank 5, contaminate the filtered liquid, and eventually deteriorate the deposition effect in the filter 10.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the filtered liquid from being contaminated and to improve the precipitation efficiency of impurities in the filter.

[0008]

According to a first aspect of the present invention, reflow soldering is performed by a saturated vapor phase formed in a vapor tank by evaporating from a liquid stored in a liquid reservoir of a vapor tank, In the filtering method in the vapor phase soldering device that performs filtering by discharging the liquid in the liquid reservoir to the filtering tank after the work in this steam tank is completed,
After discharging all the liquid from the liquid reservoir of the steam tank into the sealed filtering tank, the filtering is started by circulating the liquid through the filter around this filtering tank, and after the filtering is completed, the liquid in the filtering tank is removed. Gas phase soldering with a structure in which liquid is sent to a closed storage tank through a filter and stored in this storage tank until the liquid is returned to the liquid storage part of the steam tank when working in the steam tank. This is a filtering method in the device.

According to a second aspect of the invention, in the filtering method according to the first aspect, the start and end of the filtering are controlled by the temperature of the liquid, and the filtering is performed while the liquid temperature changes from the high temperature region to the low temperature region. Is the way.

[0010]

According to the first aspect of the present invention, the liquid after filtering is transferred from the filtering tank to another storage tank through the filter and is returned to the liquid reservoir of the steam tank when working in the steam tank. By storing the liquid in this storage tank up to this time, the contamination in the filtering tank is prevented.

According to the second aspect of the present invention, the filtering is started while the liquid is in the high temperature region, and the liquid is filtered until the liquid is cooled from the high temperature region to the low temperature region. It suppresses the precipitation of impurities in the filtering tank in the high temperature range and improves the precipitation efficiency of impurities in the filter.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in FIG.

First, the vapor phase soldering apparatus and its filtering circuit according to the present invention will be explained. The inert liquid 3 is stored in the liquid reservoir 2 of the vapor tank 1, and the liquid reservoir 2 is provided with a liquid discharge valve 4. It is connected to the sealed filtering tank 5 via the pipe line 21 containing it.

The filtering tank 5 has a cooling coil 6, a stirrer 7 and a temperature setter 8 built-in, and is provided with a filtering pipe 22 for circulating a liquid through a filter 10 and a filtering valve 11 by a filtering pump 9.

In contrast to the filtering valve 11 provided in the filtering line 22, a line including the liquid feeding valve 12
23 is branched and connected to the liquid storage tank 13. The liquid storage tank 13 is connected to the liquid reservoir 2 via a pipe line 24 including a liquid feed pump 14.

In the vapor phase soldering apparatus, a liquid heater 15 is provided in the liquid reservoir 2 of the steam tank 1, and the inert liquid 3 stored in the liquid reservoir 2 of the steam tank 1 is heated by the heater 15. It is heated and evaporated, and an inert saturated vapor phase VP is formed in the vapor tank 1. Further, a condenser (cooling coil) 16 is provided in the work carry-in part and the work carry-out part of the steam tank 1, and the steam tank 1 is condensed by the condenser 16 to condense the diffused part of the vapor phase.
The saturated vapor phase VP inside is kept within a certain range to prevent it from flowing out. Due to the latent heat of vaporization of the saturated vapor phase VP, the component mounting board P carried into the saturated vapor phase by the conveyor 18 is heated and reflow soldering is performed.

Next, the filtering method of this embodiment will be described.

By heating the liquid 3 stored in the liquid reservoir 2 of the steam tank 1 by the heater 15 to evaporate it, the steam tank 1
Saturated vapor phase VP is formed inside, and reflow soldering is performed by this saturated vapor phase VP. After the work in the steam tank 1 is completed, the liquid discharge valve 4 is opened to discharge the liquid 3 from the liquid reservoir 2 to the filtering tank 5.

After discharging all the liquid 3 from the liquid reservoir 2 of the steam tank 1 to the sealed filtering tank 5, a filtering start preset temperature (filtering high temperature of 180 ° C. or less) arbitrarily set by the temperature setter 8 is set. When the temperature reaches the start set temperature, the filtering valve 11 is opened, the filtering pump 9 is started, and the liquid is circulated through the filter 10 around the filtering tank 5 to start the filtering.

This filtering is performed until the temperature of the liquid reaches the filtering end set temperature (low temperature range such as normal temperature) arbitrarily set by the temperature setting device 8. The filtering time is determined in consideration of not only the filtering end set temperature by the temperature setter 8 but also a set time by a timer (not shown) for ensuring a necessary minimum filtering time.

As described above, the liquid set temperature for controlling the start and end of the filtering can be arbitrarily set by the temperature setter 8, and the filtering is performed while the liquid temperature is cooled from the set high temperature region to the low temperature region. By performing the above, while the impurities (flux components such as rosin) are dissolved in the high temperature inert liquid, the impurities can be efficiently supplied from the filtering tank 5 to the filter 10 while the impurities are dissolved. Impurity precipitation efficiency can be improved, and impurity precipitation in the filtering tank 5 can be suppressed.

After the filtering is completed, the filtering valve 11 is closed and the liquid feed valve 12 is opened, and the liquid in the filtering tank 5 is fed by the filtering pump 9 through the filter 10 to the closed liquid storage tank 13, and the steam tank 1 The liquid is stored in the liquid storage tank 13 until the liquid is returned to the liquid storage portion 2 of the steam tank 1 in the above operation.

In this way, the liquid after filtering is transferred from the filtering tank 5 through the filter 10 to another liquid storage tank 13, and the liquid is stored in this liquid storage tank 13, whereby the liquid in the filtering tank 13 is stored. Prevent pollution.

Finally, when the reflow soldering operation in the steam tank 1 is started, the liquid feed pump 14 from the liquid storage tank 13 is started.
To supply the liquid to the liquid reservoir 2 of the steam tank 1.

[0025]

According to the invention described in claim 1, since the filtered liquid is stored in the state of being transferred from the filtering tank to the liquid storage tank through the filter, the filtered liquid is contaminated. It is possible to prevent the possibility of being contaminated inside.

According to the second aspect of the present invention, the filtering is performed while the liquid temperature is changed from the high temperature region to the low temperature region. Therefore, while impurities such as flux components are dissolved in the high temperature liquid, this filtering is performed. Impurities can be reliably filtered, and the effect of depositing impurities on the filter is great. In other words, it is possible to reduce the residual impurities that are separated and precipitated from the liquid in the filtering tank in the low temperature region, and to reduce the contamination of the filtering tank due to the residual impurities.

[Brief description of drawings]

FIG. 1 is a sectional view and a circuit diagram showing an example of a vapor phase soldering device provided with a filtering circuit according to the present invention.

FIG. 2 is a cross-sectional view and a circuit diagram of a vapor phase soldering device including a conventional filtering circuit.

[Explanation of symbols]

 1 Steam tank 2 Liquid reservoir 3 Liquid 5 Filtering tank 10 Filter 13 Liquid storage tank VP Saturated vapor phase

Claims (2)

[Claims] 1. Reflow soldering is performed by the saturated vapor phase formed in the vapor tank by evaporating from the liquid accumulated in the liquid reservoir of the vapor tank, and the liquid in the liquid reservoir is finished after the work in the vapor tank is completed. In the filtering method in the vapor phase soldering device that discharges the liquid to the filtering tank for filtering, after discharging all the liquid from the liquid reservoir of the steam tank to the sealed filtering tank, filter around this filtering tank. After that, filtering is started by circulating the liquid, and after the filtering is completed, the liquid in the filtering tank is sent to the sealed storage tank through the filter, and when working in the steam tank, it is stored in the liquid tank of the steam tank. A method for filtering in a vapor phase soldering device, characterized in that the liquid is stored in the liquid storage tank until the liquid is returned. 2. The vapor phase soldering device according to claim 1, wherein the start and end of the filtering are controlled by the temperature of the liquid, and the filtering is performed while the liquid temperature changes from the high temperature region to the low temperature region. Filtering method in.